Fuel injection system



H. GOLD ET'AL FUEL INJECTION SYSTEM Jap. 19, 1960 4 Sheets-Sheet 1 FiledDec. 27, 1957 Eel-liars Ham/d Gold Dar/o M. Sffa/gfif Jan. 19, 1960 H.GOLD ETAL 2,921,569

FUEL INJECTION SYSTEM Filed Dec. 27, 1957 4 Sheets-Sheet 2 hum aizvaz-liar's Hero/o Go/d MOM Egg

Jam 1950 H. GOLD ETAL 2,921,569

FUEL INJECTION SYSTEM Filed Dec. 2'7, 1957 4 Sheets-Sheet 3 E517 fizz-sf/oro la Go/d 0 id 44. Sfra/ghf Lqzfi5 United States Patent ce FUELINJECTION SYSTEM Harold Gold, Shaker Heights, and David M. Straight,North Olmsted, Ohio Application December 27, 1957, Serial No. 705,573

38 Claims. (Cl. 123-'-119)- The invention relates to an improved devicefor auto matically controlling the volumetric rate of flow of liquidfuel to an engine and to a fuel injection system for injecting fuelunder pressure into the engine.

The present invention employs certain of the principles and involves amechanism and system having certain improvements over the devices shownin our copending application entitled Fuel Injection System," Serial No.594,532, filed June 28, 1956, now Patent No. 2,876,756, granted March10, 1959.

In accordance with the present invention, the flow of liquid fuel to aninternal combustion engine is controlled by a system which responds tothe various factors thatatfectengine operation. With variance of thesefactors, the normal engine operation is affected such as by affectingthe combustion of the fuel within the engine com-. bastion chambers. Thepresent inventioncontemplates an improved control system which takesinto account a greater number of the factors which affect engineoperation and compensates in a more accurate manner for the variance ofthese factors to achieve optimum control of engine running conditionsand optimum engine performance in improved fuel supply to the engine.

The basic fuel supply control system employs a fuel pump which has adelivery output which delivers a supply of fuel in accurate proportionto the speed of the engine. The fuel is delivered through a fuel flowconduit through which the fuel flows to a fuel flow which delivers fuelto the engine. A control conduit branches from the flow conduit, and avariable orifice is located between the control conduit and the branchconduit. The fuel flow control delivers fuel to the engine in accordancewith pressures in said fuel flow conduit and said control conduit.

An object of the invention is to provide a fuel control system employingthe above basic components which is provided with a simplified apparatusand method for controlling the rate of fuel delivered under idleconditions.

Another object of the invention is to provide an improved mechanism forinstallation of the fuel-flow control system on an engine.

A further object of the invention is to provide a fuel supply andcontrol mechanism of the type described wherein the variable orificebetween the fuel conduit and the control conduit employs an improvedsimplified metering rod construction for controlling the flow of fueland. the pressure in the control conduit.

Another object of the invention is to provide an improved bellowsassembly for controlling the position of the above metering rod toattain increased sensitivity to pressure changes.

Another object of the invention is to provide a simplified and improvedapparatus for regulating the fuel pressures in the fuel conduit andcontrol conduit, and in other locations in the system.

A still further objectof the invention is to v provide an mpr edarrangement for v rying back. messures n the. system.

2,921,569 Patented Jan. 19,1960

2 Another object of the invention is to. provide an improved mechanismfor removing vapor from the system during operation. Another object ofthe invention isv to provide an improved apparatus for compensating forvarying engine volumetric. efiiciency especially in engines wherein the;

efficiency peaks at mid speed range.

A further object of the invention is to provide an improved system forobtaining an enriched fuel mixture; during cold engine operation.

A still further object of the invention is to provide. an improvedsystem and apparatus for controlling fuel flow wherein idle air flowduring cold engine operation is increased.

An object of the invention isv to provide an improved fuel flow controlsystem with improved dynamic re-v sponse of fuel delivery to the enginewith sudden changes in intake manifold. pressure.

Another object of the invention is to provide. a fuel fiow controlmechanism which may be used interchange-v ably on different engineshaving different displacements, and which is provided with means foradjusting the speed characteristic of the system, to accommodate varyingengine displacements.

Another object of the invention is to provide a system' of the typedescribed wherein a delivery pump carries fuel to a fuel conduit inproportion to engine speed and employs a. positive displacement pumpwith by-pass leak-' age to. maintain pressures on both sides of the pumpequal for accurate delivery as a function of speed, and wherein the bY-PSs leakage. around the pump at, low pump. speeds is reduced.

Another object is to provide a. fuel control system wherein fueldischarge and system leakdown duringand after engine shutdown areprevented.

A still further object is to provide a fuel control sys-. tern with animproved mechanism for controlling the rate of fuel delivery duringcranking of the engine.

Another object of the invention is to provide a fuel flow system; withan improved discharge nozzle regulator assembly operative to control theflow of fuel in accordance with control pressures.

Other objects and advantages will become more apparent from theteachings of the principles of the invention in connection with thedisclosure of the preferred embodiments in the specification, claims anddrawings, in which:

Figure 1 is a diagrammatic illustration of a fuel injcction system inaccordance with the present invention;

Figure 2 is an enlarged diagrammatic cross-sectional .view illustratingthe charge forming mechanism of the Figure 5 is an enlarged fragmentarysectional view of i a valve controlled flow orifice and its accompanyingmechanism for accommodating starting conditions of the mechanism;

Figure 6 is another enlarged fragmentary sectional view, similar toFigure 5, but illustrating another form of the orifice, and associatedmechanism; and,

Figure 7 is an enlarged fragmentary elevational view of a valvemechanism of Figure 2, the view being enlarged to better illustrate itsstructure and operation.

In the description, and with reference to the drawings,

the structure and operation of the control system and the individualdevices will be divided under headings for -ease of explanation inaccordance. with the function and operation of the individual sectionsof the system.

Installation and fundamental control method In the illustratedembodiment pump shaft 1 is coupled to engine shaft A so that the pumpshaft rotates in an exact fixed proportion to engine speed. For thispurpose, the pump shaft carries a pulley 1a driven by a belt 1b whichpasses over a pulley 10 on the engine shaft A. Pump shaft 1 passesthrough a suitable seal and enters housing 2. In housing 2 shaft 1 iscoupled to gear pumps 3 and 4. Pump 3 is of a larger displacement thanpump 4. Fuel enters housing 2 from inlet line 5. Transfer pump Bdelivers fuel from tank C via conduit D to line 5 at a moderate andsubstantially constant pressure. Fuel from line 5 passes throughspring-check valve 6 to the inlet chamber 7 of pump 3. Pump 3 raises thepressure of the fuel to the operating pressure of the system anddischarges into chamber 8.

Chamber 8 is open to the inlet side of pump 4. Pump 4 discharges intochamber 9. The excess flow from pump 3 flows through passage 10 and pumpby-pass valve 11 andalso through passage 12. Pump by-pass valve 11functions to maintain the pressure gradient across pump 4 at zero.-Although not specifically illustrated, the

methods described in the previously referred to applica tion, Patent No.2,876,756, by which the various internal leakage paths from thedischarge side of pump 4 are sealed off, are to be considered to beutilized in the pres ent device. By means of this, the volumetricdelivery rate of fuel into chamber 9 is made independent of the fluidpressure in chamber 9 and is a linear function of engine speed over thefull speed range of the engine. Pump by-pass valve 11 discharges intopassage 13. Passage 13 joins the inlet chamber 14 of pressure controlvalve 15. This arrangement of flow communication, however, is adeparture from the communication of flow from the pump by-pass valve inPatent No. 2,876,756. The advantages of this modification will beexplained later. 1

The flow delivered into chamber 9 by pump 4 passes through orifice 16and into chamber 17. The flow in chamber 17 divides between variableorifice 18 and con duit 19. The flow through variable orifice 18discharges into chamber 20. Chamber 20 communicates directly withpassage 21. Chamber 20 also communicates with passage 22 through orifice23 and idle mixture control valve 24. Passage 21 communicates with inletchamber 14 of pressure-control valve 15. Passage 21 is of sufiicient'size to allow the pressure in chamber 20 to be at all timessubstantially equal to the pressure in chamber 14. Passage 19communicates with passage 25 of mounting and distributing bar 26. Fuelflows from passage 25 through the various orifices 27 and into thevarious chambers 28 of discharge-nozzle-regulator assemblies 29.Passages 19 and 25 are of sufiicient size to permit the fuel pressure atthe upstream side of each orifice 27 to be substantially equal to thepressure at the upstream side of variable orifice 18 (chamber 17).

The discharge-nozzle-regulator assemblies 29 operate to equalize thepressure downstream of each orifice 27 with the pressure communicated tothe chambers 30 of the assemblies 29. As will be explained, the pressurecommunicated to the chambers 30 is substantially equal to the pressurein chamber 20 at all engine power levels above idle running. By virtueof this pressure equalization, the pressure drop across each orifice 27is equal to the pressure drop across variable orifice 18. The rate offlow discharged by the assembly 29 is thereby funcrtionally related tothe ratio of areas of orifice 27 to the open area of variable orifice 18and to the rate of flow delivered into chamber 17. As will be explained,the open area of variable orifice 18 is varied by the movement of thebellows assembly 31 in response to the variation of the temperature andpressure of the air in the engine-intake manifold 32.

Idle mixture control In the present invention the pressure communicatedto chamber 30 of the assemblies 29 is substantially equal to, but at alltimes slightly lower than, the pressure in chamber 20. This pressurereduction, which is utilized to obtain mixture enrichment at idlerunning is obtained in the following manner. Passage 22, whichcommunicates with passage 20 through orifice 23 and idle mixture controlvalve 24, extends into chamber 33 of solenoid actuated valve 34. Whenthe engine is in operation the solenoid coil is not energized and valvedisc 35 is held in the position shown by spring 36. In this position,port 37 is open permitting flow from chamber 33 to chamber '38, andescape passage 39 leads from chamber 38 to orifice 40. Orifice 40discharges into chamber 7. Conduit 41 communicates the pressure inchamber 38 to passage 42 in bar 26 and thereby to chamber 30. Orifice 23and port 37 are large compared to the escape orifice 40. The pressuredrop across orifice 23 and valve 24 is thereby held to a small value. Asa result of the pressure drop across orifice 23 and valve 24 thepressure in chamber 30 is made slightly lower than the pressure inchamber 20. The reduction in pressure in chamber 30 results in an equalreduction in pressure in chamber 28 of assemblies 29. The reduction inpressure in chambers valve 24 is used to vary pressure drop from chamber20 to passage 22 in order to adjust the idle flow delivery for theoptimum idle mixture.

Metering rod and bellows assembly Variable orifice 18 consists oforifice 43 and contoured plug 44. Contoured plug 44 is positionedaxially in orifice 43 by metering rod 45. Rod 45 is guided in bearings46 and 47. Rod 45 is fastened in a fiuid tight and rigid manner tomovable bellows head 48. Metal bellows 49, 50 and 51 are fastened in afluid tight manner tohead 48. Chamber 5-2 encloses the assembly 31. The

three bellows are fastened in a fluid tight manner to wall 53 0f chamber52. As shown, the three bellows are in coaxial relation with rod 45.Chamber 54 of assembly 31 communicates with chamber 20 through slot 55in bearing 46. Chamber 56 of assembly 31 is sealed with' a predeterminedmass of dry inert gas. Chamber 57 of assembly 31 communicates withchamber 52 through orifice 58. Spring 59 augments the spring rate of themetal bellows to obtain the desired spring rate of the assembly 31.

Chamber 52 communicates with the engineintake manifold 32 throughconduit 60. A small amount of atmospheric air is bled into chamber 52through needle valve 61.

and passage 62. Conduit 60 is of sutficient cross-sectional area topermit the pressure in chamber 52 to be at all times substantially equalto the pressure in the engineintake manifold in spite of the air flowthrough valve 61.

Valve 61 can be utilized to adjust the idle running speed of the engine.By virtue of the pressure and flow communication with chamber 52, theassembly 3 1 is exposed to the pressure of the air in the engine-intakemanifold and the temperatureof the air flowing into the intake manifold.1

Under steady running conditions the air pressure in chamber 57 of theassembly 31 is equal to the pressure in chamber 52. Thus under steadyrunning conditions bellows 49 acts only as a spring. The object oftheaddition of bellows 49 is to improve the response Of the bellowsto-changes' in intake manifold a change in pressure in chamber 52 thenew pressure acts immediately on the outside face of head 48. Thepressure in chamber 57 will follow the pressure in chamber 52 at a ratedetermined by the flow resistance of orifice 58 and file compressibilityof the air in chamber 57. Until the pressure in chamber 57 equalizeswith the pressure in chamber 52, the pressure difference acting on theannular area of head 48 between bellows 49 and 50 creates a drivi'ngforce on head 48. This added driving force improves the sensitivity ofthe bellows assembly to pressure changes and quickens the movement ofthe assembly.

The addition of the air bleed through valve 61 will improve the responseof the bellows assembly to changes in intake air temperature. Thebellows assembly moves in response to temperature changes throughexpansion or contraction of the dry inert gas in chamber 56.

Chamber 54 of assembly 31 communicates with chamber 20 and hence withthe pressure downstream of variable orifice 18. In the systems describedin application Serial No. 450,428, now Patent No. 2,876,755, grantedMarch 10, 1959, and Patent No. 2,876,756, this communication is madewith the pressure upstream of the variable orifice. The presentmodification is made to permit correction for variations in engine backpressure and correction for varying engine volumetric efficiency whenthe efficiency "pea.ks in the mid-speed range. These corrections will bedescribed in later paragraphs.

The contoured plug 44 decreases the open area of variable orifice 18 asmetering rod 45 moves toward orifice 43. It may, therefore, be seen thatat a fixed engine speed an increase in intake manifold pressure causesan increase in fuel delivery, an increase in inlet air temperaturecauses a decrease; and an increase in fuel pressure in chamber 20 causesa decrease.

Pressure control valve, back-pressure correction and vapor eliminationThe pressure in passage 20 and hence in chamber 54 is controlled bypressure control valve 15. Pressure control valve 15 consists of orifice63 and conical plug 64. Plug 64 is fastened to diaphragm plate 65. Limpdiaphragm 66 is clamped between plug 64 and diaphragm plate 65 and isfastened to the walls of chamber 67, thereby forming a liquid-tight,movable wall between chambers 67 and 14. Cylindrical rod 68 is integralwith plug 65 and maintains plug 65 coaxial with and perpendicular toorifice 63. Rod 68 is retained in bore 69. Spring 70 biases plug 64 intoorifice 63. Fuel pressure in chamber 14 acting on the annular area ofdiaphragm 66 (bounded by the wall of chamber 14 and the periphery oforifice 63) creates a force opposite to the spring bias. Fuel pressurein chamber 71 acting on plug 64 also creates a force opposite to thespring bias. Orifice 63 opens into chamber 71. Chamber 71 communicateswith chamber 7 through orifice 72 and passage 73. Chamber 71 alsocommunicates with tank return line 74 through orifice 75 and passage 76.Orifice 72 is large compared to orifice 75. Chamber 67 communicates withthe atmosphere through vent,77. Atmospheric pressure acting on the fullarea of diaphragm 66 creates a force in the same direction as the springbias.

As now described, the pressure in chamber 14 is a function of the axialforce balance between the spring bias force and the. forces that resultfrom the pressures in chambers 14, 67 and 71. When the engine speed isvaried, the flow into valve 15, from pump bypass valve 11 and variableorifice 18, varies. An increase in flow through valve 15 causes plug 64to move out of orifice 63. This movement causes compression of spring 70and hence an increase in spring bias. The increase in spring bias isoffset by the increase in upward force that results from the increase inpressure in chamber 71 due to the increase in flow through orifices 72.and 75. This method of modifying the pressure regulation of a springbiased, pressure responsive valve by means of a series of flowrestrictions is an application of the principle given in 23' at PatentNo. 2,876,756 and in said patent a spring-biased; pressure-responsivevalve is employed as the series restric tion. This more complex flowrestriction was because in that charge forming device the flow into thepressure regulating valve is only the flow by-passed by thebellows-actuated variable orifice. Because of this flow communicationthe flow range through the pressure regulating valve extended to lowvalues where a simple flow restriction would have no effect. In thepresent device, the flow into valve 15 is the sum of the flows fromvari-' able orifice 18 and the pump by-pass valve 11. The a'ddi tion ofthe flow from valve 11 increases the minimum flow sufiiciently to allowthe use of the simple flow restriction to obtain the required accuracyof pressure regulation.

By virtue of the atmospheric vent to chamber 67, the pressure in chamber14 will rise and fall directly was variations in atmospheric pressure.This pressure variation causes a corresponding movement of rod 45 andvariation of the open area of variable orifice 18. As atmosphericpressure decreases (such as with increasing altitude) the correspondingdecrease in pressure in chamber 54 causes a reduction in the open areaof variable orifice 18 and hence an enrichment of the charge. Thiseffect is utilized to correct the fuel delivery for the reduction inengine back pressure that occurs with increasing altitude.

By means of the tank return path from chamber 71 vapor that is formed atthe discharge from orifice 63 is substantially prevented from returningto the inlet of pump 3. Orifice holds the bleed back flow to the desiredlimit.

Compensation for variation of volumetric efiiciency withspeed 17. By themeans that will now be described, the rate of fuel delivery into chamber17 may be made to vary in either a linear or a non-linear relation withengine speed. By this means the rate of fuel delivery to the engine canbe made to vary in either a linear or a nonlinear relation with enginespeed.

In the case of engines that utilize resonant intake manifolds, there isan effective peak in volumetric efficiency in substantially themid-speed range. To accommodate this type of engine, the fuel delivery,at. con.- stant intake-manifold pressure and intake air tempera ture,must increase in greater than linear proportion in. the lower half ofthe speed range and increase in less than linear proportion in the upperhalf of the speed range as the engine speed is varied from low speed tomaximum speed. This compensation is provided through variable orifice79. Variable orifice 79 consists of a contoured plug 78 that ispositioned in the orifice 79. Plug 78 is fastened in a fluid-tightmanner to limp diaphragm 80 and diaphragm plate 81. Stem 82 is guided inbore 83 to hold plug 78 concentric with and perpendicular to orifice 79.Diaphragm 80 is fastened to the wall of chamber 84 to form aliquid-tight movable wall between chambers 84 and 85. Spring 86 biasesdiaphragm 80 toward chamber 84. Chamber 84 communicates with chamber 8through passages 87 and 12. Chamber communicates with chamber 17 throughpassages 88 and 89. Orifice 79 opens into chamber 90. Chamber 90communicates with chamber 17 through passages 91 and 89. The passagesare of sufficient size so that the pres variable orifice 79 issubstantially equal to the pressure drop across orifice 16. By virtue ofthe equality of pressure drops the flow rate contributed to chamber 17by variable orifice 79 is proportional to the flow rate contributed bypump 4 and to the open area of variable orifice 79. The open area ofvariable orifice 79 is varied by the movement of diaphragm 80 againstspring 86 and is thereby controlled by the rate of flow from pump 4.Thus the flow added into chamber 17 by variable orifice 79 is completelycontrolled by engine speed. By the proper contouring of plug 78 thevariation of flow added to chamber 17 can be adjusted to vary the rateof fuel delivery of the system with speed to match a wide variety ofvolumetric efiiciency speed variations. In the case of engines thatexhibit constant volumetric efiiciency with speed, variable orifice 79is eliminated.

Cold-running compensation The control principle given in claim 21 ofPatent No. 2,876,756 is also utilized in the present device to obtainenrichment of the charge during operation with a cold engine.Cold-enrichment variable orifice 92 may be seen to communicate withchambers 8 and 17 in the same manner as this communication is brought tovariable orifice 79. Therefore, the flow added by variable orifice 92 isproportional to the flow through orifice 16, the constant ofproportionality being equal to the ratio of the open area of variableorifice 92 to the area of orifice 16.

Variable orifice 92 consists of orifice 93 and tapered plug 94. Taperedplug 94 is integral with seal piston 95, rod 96 and spool 97. Metalbellows 98 pushes against spool 97 urging the assembly against spring99. Bellows 98 communicates with bulb 100 through capillary tube 101,Fig. l. The bulb, capillary and bellows are sealed full of a suitableliquid. Bulb 100 is inserted in a region indicative of engine operatingtemperature such as the engine water jacket E.

When the engine is cold, the liquid in bulb 100 contracts causingcontraction of bellows 98, Fig. 2. Plug 94 is then drawn out of orifice93 by spring 99. When the water jacket temperature is raised byoperation of the engine, the expansion of the liquid in bulb 100 movesplug 94 into orifice 93, thereby gradually reducing the enrichment flow.When the water jacket temperature approaches the normal limit, plug 94seats against orifice 93 to cut off the enrichment flow entirely.

Bellows 98 is fastened at its fixed end to piston 102. Piston 102 isurged against shoulder 103 in bore 104 by spring 105. In the event ofover temperature of the water jacket, spring 105 takes up the excessexpansion of bellows 98 thereby preventing damage to variable orifice 92or bellows 98.

As may be seen, bellows 98 simultaneously actuates spool 97 and plug 94.Spool 97 moves in annulus 106 to form a flow controlling valve. Annulus106 communicates with the atmosphere through passage 107. Spool 97 opensannulus 106 to chamber 108. Chamber 108 communicates with passage 62through passage 109. By the previously described action of bellows 98,spool 97 and annulus 106 provide an automatic valve that providesincreased airflow to the engine at idle (throttle F closed), when theengine is cold.

Dynamic response Upon sudden opening of the engine throttle F, Fig. 1,the pressure in the intake manifold. increases very rapidly. Theresponse of fuel delivery to the sudden increase in intake manifold isdelayed in inertial and capacitive 7 effects associated with the flow ofliquids. In order to ob tain good engine acceleration characteristics,it is necessary to compensate for this natural lag. This compensation isobtained in the present device through derivative element 110, Fig. 2.

Derivative element 1 10 consists of piston 111 operating in bore 112 andsealed against fuel leakage by limp dia phragm 113. Limp diaphragm 113seals fuel in chamber 114. Chamber 114 communicates with chamber 17through orifice 115. Fuel pressure in chamber 17 urges piston .111against spring 116. Spring 116 is retained in chamber 117. Chamber 117communicates directly with chamber 52 and hence withengine-intake-manifold pressure. Spring 116 maintains the forceequilibrium between the higher fuel pressure and the intake manifoldpressure that act on opposite sides of piston 111. Spring 116 is soconstructed that it maintains the force balance under the condition oflowest intake-manifold pressure When the piston 111 is at substantiallythe upper end of its stroke (as shown in the drawings). Under thecondition of highest intake-manifold pressure, the forcebalance ismaintained when the piston 111 is at the lower end of its stroke. Thedownward and upward movement of piston 111 with increasing anddecreasing intake-manifold pressure causes fuel to be added to or drawnaway from chamber 17. This action causes the pressure in chamber 17 tomomentarily rise above the steady running pressure when intake manifoldpressure rises, and to momentarily fall below the steady runningpressure when intakemanifold pressure falls. The momentary excesspressure charge in chamber 17 overcomes the physical lags in delivery offuel from chamber 17 The rate of change of pressure in chamber 114, issubstantially, instantly equal to the rate of change of intake manifoldpressure (or to the derivative of manifold pressure). The rate of flowinto or out of chamber 114 in response to pressure variations in chamber114 is controlled by orifice 115. The magnitude of the pressure pulsecreated in chamber 17 and passage 25 following a sudden change inintake-manifold pressure can be varied by adjustment of the area ofpiston 111, the rate of spring 116 and the area of orifice 115. Thisadjustment may be made to obtain the optimum accelerationcharacteristics.

Upon a sudden opening of the engine throttle F of large magnitude thesharp rise in intake-manifold pressure acting on bellows assembly 31causes (through the previously explained action of bellows 49) rod 45 tobe momentarily over driven. This over shoot causes shoulder 118 to seatagainst orifice 43, and momentarily cutoff the by-pass fiow from chamber17. By means of this cut-off action, all flo'ws entering chamber 17 aremomentarily delivered to the assemblies 29 alone. The resulting sharpincrease in flow discharge permits smooth acceleration following severethrottle manipulations.

Engine displacement compensation It is a practice in the automotiveindustry to build engines that are similar in operating characteristicsbut that differ in piston displacement. One assembly (as encompassed inhousing 2) can be utilized interchangeably for such a group of enginesif means are provided for adjustment of the linear rate of delivery offuel into chamber 17 with engine speed. As previously described, alinear delivery is contributed by pump 4. Orifice 119 provides a meanswhereby a second (adjustable) linear delivery contribution can be made.

Shaft 120 of plug 121 passes through a suitable seal and engages threadsin housing 2. Rotation of shaft 120 causes tapered plug 121 to vary theopen area of orifice 119. Fuel flows from chamber 8 through passages 12and 122 to the upstream side of orifice 119 and co'mmunicates withchamber 17 through passages 123, 91 and 89. By means of the hydraulicprinciple previously explained in conjunction with, variable orifices 79and 9 2,

assigns 9 the new that passes through orifice 119 proportional to theflow through orifice 16, the ratio of the two flows being equal to theratio of the two open orifice areas. Once adjusted, the open area oforifice 119 remains fixed, hence the flow contributed to chamber 17 byorifice 119 is linearly proportional to engine speed. Adjustable orifice119 can also be used to compensate for manufacturing variations in thedisplacement of pump 4.

Pump by-pass valve With reference to valve 11, it was pointed outpreviously that the valve discharges into passage 13. The pressuredifference between passage 10 and passage 13 is equal to the pressuredifference between passage 9 and passage 21. Hence, the pressure dropbetween passage 10 and passage 13 is equal to the pressure drop acrossorifice 16 plus the pressure drop across variable orifice 18. Thepressure difference between sealing annulus 124 and discharge annulus125 is equal to the pressure difference between passages 10 and 13.Annulus 124 cominunicates with passage 10 through passage 126 in piston127. The leakage flow from annulus 124 to annulus 125 is proportional tothe pressure difference between them. At low speed conditions. thepressure drop across orifice 16 and across variable orifice 18 is verysmall. Hence, at low speed conditions the leakage flow from annulus 124to annulus 125 is very small. It is of advantage to hold this leakageflow small at low speed because the output of pump 3 is then at aminimum.

Shut-down Upon shut-down, the action of check valve 6, solenoid valve34, shut-down valve 128, and the inherent cut-off action of thedischarge-nozzle-pressure-regulator assemblies 29 cause fuel to betrapped in housing 2, the assemblies 29 and the connecting passages.Immediately following shut-down there is a momentary continuation offlow of fuel through orifice 75 and passage 74 back to tank C. This flowis stopped by shut-down valve 128 when the pressure in chamber 14 dropsa small amount below the operating pressure.

Valve 128 is a pressure-responsive, double acting valve. The pressureresponsive element, diaphragm 129 forms a liquid-tight movable wallbetween chambers 130 and 131. Rigidly connected to diaphragm 129 arevalve discs 132 and 133. Valve disc 132 coacts with port 134 and valvedisc 133 coacts with port 135. Spring 136 biases diaphragm 129 towardchamber 130. Port 134 communicates chamber 130 with chamber 137. Chamber137 communicates with chamber 17 through passage 138. Port 135communicates chamber 131 with orifice 75. Chamber 131 communicatesdirectly with passage 74. Chamber 130 communicates with chamber 14through passage 1 39.

During operation of the engine, the fuel pressure in chamber 130,communicated from chamber 140 drives diaphragm 129 against spring 136.In this case (as shown in the drawings) valve disc 132 closes off port134 and valve disc 133 is lifted to open port 135. In this position, theflow of vapor into passage 74 is permitted as previously described.Immediately after the engine speed is reduced to zero, port 135 remainsopen permitting the pressurized system to bleed down. However, when thepressure in chamber 130 reduces to a predetermined value, spring 136moves diaphragm 129 toward chamber 130 thereby causing disc 133 to sealoff port 135. The same action causes disc 132 to open port 134.

With port 134 open a static pressure equalization is brought aboutbetween chambers 17 and 20. This equalization cannot be provided byvariable orifice 18 because shoulder 118 normally seats against orifice43 during shut-down. W h the pre r s n cham ers 7 and 20 fialized,passages 25 and 42 remain at equal pressures.

pressure in chamber 28 must then be equal to or 10 lessthan the pressurein chamber 30. when-rhesus: sures in chambers 28 and 30 are equal thereis a closing force that drives valve disc against seat 141 in assemblies 29, Fig. 4. The closing force results from the pressure unbalanceat the valve disc 140. Fuel pressure in chamber 30 urges the discagainst the seat. In chamber 28 the fuel pressure cannot act on the discwhere it seals off the discharge bore.

Starting-flow control When the engine is started by cranking with aconven tional electric-starter motor, the low rotational speed of pumps3 and 4 during cranking does not provide sufiicient pump out-put toraise the system pressure high enough to close port 134 of valve 128 andpermit the assemblies 29 to discharge. Solenoid valve 34 and theassociated passages provide the means whereby the discharge flow fromthe assemblies 29 is maintained and controlled din ing cranking.

Coil 175 of solenoid 34 is connected to the electrical circuit of thestarter motor so that the coil is energized when the starter motor isenergized. Thus, armature 142 is drawn against spring 36 by the magneticpull of coil 175 whenever the engine is being rotated by the startermotor. Armature 142 draws valve disc 35 away from orifice 143 and towardport 37. By this action, orifice 143 is opened and port 37 is closed.Orifice 143 discharges into passage 144. Passage 144 communicates withpassage 74.

Boost pump B, Fig. 1, delivers fuel to inlet pipe 5 at the normaloperating pressure at cranking speeds. Check valve 6, Fig. 2, which isvery lightly spring biased, creates only a negligible pressure loss.Thus, during cranking a substantially constant and predetermined fuelpressure is maintained by conventional means in chamber 7. Duringcranking, fuel flows from chamber 7 through orifice 40, along passage 39and through orifice 143 into pass sage 144 from which the fuel returnsto tank C, Fig. 1, via passage 74. It will be noted that the directionof flow through orifice 40, Fig. 2, is, during the cranking, the reverseof the direction of flow during engine running. Fuel also flows fromchamber 7 through pump 3 to chambet 8, due both to forward leakage andto the small pumping action of pump 3 at cranking speeds. From chamber 8the fuel flows through pump 4 to chamber 9 also due to forward leakageand to the small pumping action of pump 4 at cranking speeds. Fuelflowing through pump 4 passes through orifice 16 into chamber 17. Fuelmay also flow from chamber 8 to chamber 17 through the several auxiliarypaths that were previously described.

As previously pointed out in the description of the idle mixturecontrol, orifice 40 is made relatively small in order to satisfy therequirements of the idle mixture control. During cranking, the flowresistance offered by orifice 40 is great compared to the forward flowresistance of pumps 3 and 4 and the associated passages. By virtue ofthis, fuel from boost pump B, during cranking, reaches chamber 17 withsubstantially no loss in pressure. Fuel flowing through orifice 40 maysuffer a significant pressure loss. Thus during cranking, the fuelpressure communicated to passage 25 from chamber 17 can be made greaterthan the fuel pressure communicated to passage 42, from chamber 38. Thepressure in chamber 38 is determined by the flow resistance of orifice143 and the rate of flow into chamber 38. The rate of flow into chamber38 is the flow through orifice 40 plus the auxiliary flow throughorifice 145. Orifice 145 by-passes port 37 and is not sealed off by disc35. Orifices 143 and 145. can be varied independently of orifice 40 tovary the pressure in chamber 38 and thereby vary the rate of fueldelivery during cranking. Thus the idle mixture circuit is not disturbedby variation of the starting control circuit. If the flow deliveryduring cranking 7 11 a, temperature actuated plug similar to plug 94 canbe used in conjunction with either-orifice 143 (94a) Fig.5, or 94b withorifice 145, Fig. 6. s

. Discharge-nozzle-regulator assemblies The discharge-nozzle-regulatorassemblies 29, Figs. 2 and 4, operate in accordance with the hydraulicprinciple set forth in Patents 2,876,755 and 2,876,756. In the presentdevice several important modifications have been made that yieldimprovement in the following characteristics: accuracy of pressureregulation at very low flow rates, tightness of cut-off and ease ofassembly.

The assembly 29, Fig. 4, is enclosed in housings 146 and 147. Housing146 contains a recess 176 which encloses chamber 28. A seat 141 projectsupward from the recess 176. Housing 147 contains a bore 148 which matessnugly with the outside of a wall 149. A limp diaphragm 150 is clampedbetween the top of wall 149 and a clamping surface 151. The wall 152 ofchamber 30 projects perpendicularly from surface 151. Bore 153 projectsfrom chamber 30 coaxially-with wall 152. By means of the mating fitbetween bore 148 and wall 149 concentricity is assured on assemblybetween bore 153, wall 152, the wall 149 and discharge orifice 154, thecommon axis being perpendicular to the clamping plane of the diaphragm150. A disc 140 is made of an elastic material. The disc is fastened toretainer 155 in recess 156. Diaphragm 150 is fastened to retainer 155along flange 157 by plate 158 and nut 159. Stem 160 of re tainer 155fits slidably in bore 153 to maintain disc 140 and plate 158 concentricwith and parallel to seat 141.

The surface of seat 141 is an annulus, the inner circle of the annulusbeing the bore of orifice 154. The thick ness of the annular surface ispreferably small to obtain sufiicient deformation of disc 140 with thesmall seating force that is available at shut-down for fluid-tightshutoff.

' The depth of recess 156 and the thickness of disc 139 are proportionedto hold the exposed surface eof disc 140 in substantially the plane ofthe upper surface of clamping flange 157. Seat 141 lies in a commonplane with the top of wall 149. Therefore, when disc.14-1 contacts seat140, diaphragm 150 is held fiat and unstressed. At low discharge flowrates the lift of disc 141 from seat 140 is very small compared to theouter clamping diameter of diaphragm 150. Thus the pressure regulationerror introduced by diaphragm distortion is very small. This reductionof pressure regulation error is very significant because the pressuredrop across orifice 27 is of this relative magnitude at low dischargefiow rates.

The mounting sides of housings 146 and 147 are in a common flatplane-where the assembly is fastened to bar 26. Suitable fasteners, notshown, hold assembly 29 against bar 26 and hold housings 146 and 147together- Chamber 30 communicates with passage 42 through pas-- sage 161and chamber 28 communicates with passage 25 through passage 162. Passage161 is sealed against bar 26 by sealing ring 163. Ring 163 is retainedin recess 164 in housing 147. Orifice 27 is retained in recess 165 inhousing 146. Recess 165 also retains seal ring 166. Screen 167 isintegral with seal ring 166.

Discharge orifice 154 opens into enlarged passage 168. Passage 168preferably penetrates the bore of discharge.

orifice 154 to reduce the length of the bore to the minimum that ispractical. A finite length is necessary to maintain dimensionalreproducibility on the diameter of orifice 154. Passage 168 opens intoenlarged passage 169. Spool 170 engages housing 146 and boss 171 inintake-manifold 32 to form a substantially air-tight seal. Air is bledinto passage 168 through passage 172 and orifice 173. This air bleedserves to atomize the fuel when the discharge flow rate is very low. Athigh flow rates the fuel discharging through orifice 154 penetrates in astream directly into the intake manifold. This penetration is improvedby the short length of orifice 154 and the expanding walls of passages168 and 169. The pcnc- 7 condui s downstream of said fixed and idleorifices and tial period following engine shut-down.

diately following sudden large opening of the engine throttle F. In thisperiod the air bleed through orifice 173 is reduced to essentially zero.The penetration of the discharge stream prevents the wetting of thewalls of passages 1 68 and 169 that is otherwise prevented by the airbleed. The time required for droplet emission from 'the wetted wallswould cause a significant delay in engine response to sudden throttleopenings.

Spool is preferably constructed of a thermally insulating material toreduce heat absorption of the assemblies 29 after engine shut-down. Theair gap provided between the assembly and the intake manifold permitsthe assemblies to be cooled by natural convection. These considerationsare of importance because the temperature of the intake manifold risesvery sharply in the ini- During shutdown, heat fiow from the engineblock is not dissipated by the flow of air through the intake manifoldas during operation.

Thus, it will be seen that we have provided an improved fuel =fiowcontrol system which meets the advantages and objectives hereinbeforeset forth. It will be understood that while the system is shown asoperating to its best advantage with the various components operating incombination with other components, that the principles and features maybe utilized with other components taking advantage of their inherentfeatures.

We have, in the drawings and specification, presented a detaileddisclosure of the preferred embodiments of our invention, and it is tobe understood that we do not intend to limit the invention to thespecific forms disclosed, but intend to cover all modifications, changesand alternative constructions and methods falling within the scope ofthe principles taught by our invention.

We claim as our invention:

1. In a fuel supply system for an engine, a fuel conduit, means forsupplying fuel to said conduit at a rate proportional to engine speed, afixed orifice in said fuel conduit, a control conduit leading off saidfuel conduit upstream of said fixed orifice, a variable orificeconnecting the control conduit to said fuel conduit and variable to varythe fuel fed to the engine, a variable idle mixture control orificemeans in said control conduit, an escape conduit leading from saidcontrol conduit downstream of said variable idling mixture controlorifice, a fixed orifice in the escape conduit being of a size smallerthan said variable idle mixture control orifice whereby the pressuredrop across the idle mixture control orifice is small to have minimumeffect at running speeds, and fuel flow control means connecting to saidfuel conduit and said control conduit and operative to supply fuel tothe engine responsive to pressures in said conduits.

2. In a fuel supply system for an engine a fuel conduit, means forsupplying fuel to said conduit at a rate proportional to engine speed, afixed orifice in said fuel conduit, a control conduit leading off saidfuel conduit upstream of said fixed orifice, a variable orificeconnecting the control conduit to said fuel conduit and variable to varythe fuel fed to the engine, a fixed orifice in said control conduit, andfuel flow control means connecting to both of said conduits downstreamof said fixed orifice and opera tive to supply fuel to the engineresponsive to the pressures in said conduits.

3. In a fuel supply system for an engine, a fuel conduit, means forsupplying fuel to said conduit at a rate proportional to engine speed, afixed orifice in said fuel conduit, a control conduit leading off saidfuel conduit upstream of said fixed orifice, a variable idle mixturecontrol orifice in the control conduit having a pressure dropthereacross which is small in relation to the drop across said fixedorifice at running speeds and relatively large at idling speeds, and afuel flow control means connecting to both of said 13 operative tosu'pply fuel to the engine responsive to pressures in said conduits.

4. In a fuel supply systernfor an engine, a fuel conduit, means forsupplying fuel to said conduit at a rate proportional to engine speed, afixed orifice in said fuel conduit, a control conduit leading off saidfuel conduit upstream of said fixed orifice, a variable orificecontesting the control conduit to said fuel conduit and variable to varythe fuel fed to the engine, a fixed orifice its-said control conduit, a'variable idling mixture contrfit valve by-passing said fixed orifice inthe control conduit, and fuel flowcontrol means connecting to bothOf'said; conduits downstream of said fixed orifices and operative tosupply fuel to the engine responsive to the pressures in said conduits-.

5. A fuel control and supply assembly for an engine a fuel flow supplyconduit, means for delivering fuel to said conduit at a rateproportional to the speedof an engine, a control conduit, a variableorifice connecting between said fuel and control conduit and having amovable valve element with a contoured external surface shaped toprovide a desired flow with linear movement relative to the orifice, afixed orifice in said conduit downstream of the control conduit, andfuel flow control means connected to said conduits and supplying fuel totheengine in accordance with pressures in said conduits.

v 6, A fuel control and supply assembly for an engine comprising a fuelflow supply conduit, means for delivering fuel to said conduit at a rateproportional to the speed of an engine, a control conduit, a variableflow valve means connected between the fuel conduit and control conduit,first means responsive to intake manifold pressure and connected forcontrolling the opening of thefiow valve, second means responsive tochange iii-intake manifold pressure accelerating the change in openingof said valve means whereby a more rapid response in'fuel supply changewill be obtained, a fixed ol mcein said fuel vconduit downstream of thecontrol conduit, and fuel flow control means connected to said conduitsand supplying fuel to the engine in accordance with pressures in saidconduits. 1

"I; A fuel control and supply assembly for an engine comprising a fuelflow supply conduit, means for delivcring fuel to saidconduit at a rateproportional to Ibo-speed of an engine, a control conduit, a variableflow valve means connected between the fuel conduit andcontrol-jconduit,first means responsive to intake manifold pressure and connected forcontrolling the opening of the flow valve, second means also responsiveto elungs in intake manifold pressure-and augmenting the forecofthe-first means to change the opening of said valve meanu'a fixedorifice in said fuel conduit down stream of the control conduit, andfuel flow control means connected to said conduits and supplying fuel tothe engine in accordance with pressures in said conduits.

, 8. A fuel control and supply assembly for an engine a fuel flow supplyconduit, means for delivering fuel to said conduit at a rateproportional to the speed of an engine, a control conduit, a variableflow. valve meansconuected between the fuel conduit and control conduit,first means responsive to intake manifold'pressure-and connected .forcontrolling the opening of the flow valve, an cxpansible bellows havinga movableportlon connected to said flow valve and operative mrchange theopening with expansion or contraction, n'nansexpos'ing one surface ofthe bellows to the engine manifold pressure, a bleed opening through thebellows whereby a change in manifold pressure will cause a force on thebellows which diminishes as the pressure leaks through the bellows andthe pressures on both sides oqualine, a fixed orifice in said fuelconduit downstream of the control conduit, and fuel flow control meanscon mm to saidconduits and supplying fuel to the engine in 'occordoncewith pressures in said conduits a a 14 9a A fuel eontrol and supply.assemblyfor an engine comprising-a fuel fiowsupply conduit, means fordelivers ing fuel to' said conduit at a rate proportional to the speedof anengine, a control conduit, avariable flow valvemeans connectedbetween the fuel conduit and control conduit, temperature responsivemeans connected to said valve means, means defining a chamber housingsaid temperature responsive means, a passageway communicating betweensaid chamber and the intake manifold of the engine, an air bleed openinginto said chamber whereby the temperature responsive means will beexposed to ambient air of the same temperature that enters the engine,and means operati-vely connected to said conduit and supplying fuel tothe engine in accordance with pressures in said conduits.

10. A fuel control and supply assembly for an engine comprising a fuelflow supply conduit, means for deliven ing fuel to said conduit at arate proportional to the speed of an engine, a control conduit, avariable flow valve means connected between the fuel conduit and control conduit, pressure responsive means connected to said valve means tocontrol the opening with changes in pressure in an intake manifold ofthe engine, means defining a chamber to house the pressure responsivemeans, a passageway communicating between said chamber and the intakemanifold of the engine, an air bleed opening into said chamber, anadjustment member for said air bleed opening whereby the air flow intothe chamber can be varied to adjust the idling speed of the engine, andmeans operatively connected to said conduits and supplying fuel to theengine in accordance with pressures in said conduits.

11. A fuel control and supply assembly for an engine comprising a fuelflow supply conduit, means for deliver-v ing fuel to said conduit at arate proportional to the speed of an engine, a control conduit, avariable flow valve means connected between the fuel conduit and controlconduit, a temperature responsive bellows con.- nected to said valve, afirst pressure responsive bellows connected to said valve, a secondpressure responsive bellows connected to said valve, a chambersurrounding said bellows, a bleed passageway through said second bellowscommunicating with said chamber whereby pressure. changes in the chamberwill cause an instantaneous but diminishing effect on said secondbellows, a passageway between the bellows chamber and the intakemanifold of the engine, an air bleed opening into said chamber where. bythe temperature responsive means will be exposed to ambient air of thesame temperature that enters the engine, an adjustment member for saidair bleed opening whereby the air flow into the chamber can be varied],to adjust the idling speed of the engine, and means opera, tivelyconnected to said conduits and supplying fuel to the engine inaccordance with pressures in said conduits,

12. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speedof an engine, a control conduit branching from the fuel conduit, avariable orifice between the fuel conduit and the control conduit, afuel flow control connected to deliver fuel to the engine in accord-,ance with pressures in said conduits, a pressure regulator valve openingfrom said control conduit to a lower pressure and automatically varyingin opening with variance in pressure in the control conduit, and meansfor supplying additional fuel to said control conduit to improve theaccuracy of said pressure regulator valve at idling speeds of theengine.

13. A fuel supply mechanism for an engine comprising a fuel flowconduit, a first positive displacement fuel pump in said conduitoperated in proportion to the speed of the engine, a second positivedisplacement pump in series with the first and driven proportional toengine speed, a bypass valve connected to the second pump output andresponsive to pressure differential across said pump to bleed fuelfromthe pump intake and cause the output to be accurately proportional tovspeed, a control conduit branching from the fuel conduit, avariableorificc between the fuel conduit and the control conduit, a fuelflow control connectedv to deliver fuel'to the engine in accordance withpressures in said conduit, a pressure regulator valve opening from saidcontrol conduit to a lower pressure and automatically varying in openingwith variance in pressure in the control conduit, and a passagewaydirecting the flow of fuel from said by-pass valve to said controlconduit to increase the flowthrough the pressure regulator valve andincrease its accuracy.

14. A fuel supply mechanism for an engine comprising a fuel flowconduit, a fuel pump in said conduit, a control conduit branching fromthe fuel conduit, an orifice between the fuel conduit and the controlconduit, a fuel flow control connected to deliver fuel to the engine inaccordance with pressures in said conduits, a flow opening from saidcontrol conduit to obtain a flow therethrough discharging to an inlet tothe fuel pump, and a small vapor preventing bleed orifice between thepump inlet and the flow opening to discharge vapor formed at the flowopening and prevent it from entering the fuel pump inlet.

15. A fuel supply mechanism for an engine comprising a fuel flowconduit, a positive displacement fuel pump in said conduit operated inproportion to the speed of the engine, a fuel tank connected to supplyfuel to said pump, a control conduit branching from the fuel conduit, avariable orifice between the fuel conduit and the control cnduit, a fuelflow control connected to deliver fuel to the engine in accordance withpressures in said conduits, a pressure regulator valve opening from saidcontrol conduit to a lower pressure and automatically varying in openingwith variance in pressure in the control conduit, said regulator valvedischarging to an inlet to the fuel pump, and a small bleedvapor-preventing orifice between the pump inlet and the regulator valveand leading to the fuel tank to permit the vapor formed at the valve toflow to the fuel tank and prevent it from entering the pump inlet.

16. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speedof an engine, a control conduit branching from the fuel conduit, avariable orifice between the fuel conduit and the control conduit, afluid flow control connected to deliver fuel to the engine in accordancewith pressures in said conduits, and means for varying the fuel flowrate in said fuel conduit non-linearly with speed increase to compensatefor change in volumetric efiiciency of the engine.

17. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speedof an engine, an orifice in said fuel conduit, means for controllingfuel flow to the engine in accordance with the pressure in said fuelflow conduit downstream of said orifice, and pressure responsive meansconnected to operate responsive to pressure differential across saidorifice and connected to vary the pressure in the fuel flow conduitdownstream of said orifice to obtain fuel flow rates that increasenon-linearly with increase in engine speed to compensate for change involumetric efliciency of the engine with speed change.

18. A fuel supply mechanism for an engine comprising a fuel flowconduit, pump means supplying fuel to the conduit in proportion to thespeed of an engine, an orifice in said fuel conduit, means forcontrolling fuel flow to the engine in accordance with the pressure insaid fuel flow conduit downstream of said orifice, means forpressurizing the intake side of said pump equal to the pressure of thedischarge side whereby the pump output is accurately proportional toengine speed, a passageway from the intake side of said pump to thedownstream side of said orifice, a variable volumetric efiiciencycompensab ing valve connected to permit a fuel flow past the pump and te Q i 9 the f el conduit, n m a ope ing 16 said volumetric efficiencyvalve as a function of yengine speed non-linearly with speed changetovary the pressure in the fuel conduit downstream of said orificenon-linearly to compensate for variation in volumetric efficiency of theengine at different speeds. L

19. A fuel supply mechanism for an engine comprising a fuel fiowconduit, pump means supplying fuel to the conduit in proportion to thespeed of an engine, a control conduit branching from the fuel conduit, avariable orifice between the fuel conduit and the control conduitcontrolling the fuel flow rate in said control conduit independent ofvariations in engine speed, a fuel flow control connected to deliverfuel to the engine in accordance with pressures in said conduits, a coldrunningcm richment fuel passageway leading'into said fuel conduit tosupply additional fuel for cold running, means for deliveringpressurized fuel to said enrichment passageway, and a temperatureresponsive valve means in said enrichment passageway and operative toclose with increase in engine temperature.

20. A fuel supply mechanism for an engine comprising a fuel flowconduit, pump means supplying fuel to the conduit in proportion to thespeed of an engine, a control conduit branching from the fuel conduit, avariable orifice between the fuel conduit and the control conduitcontrolling the fuel flow in said control conduit independent ofvariations in engine speed, a fuel flow control connected to deliverfuel to the engine in accordance with pressures in said conduits, anorifice in said fuel conduit, a cold running enrichment fuelpassageway-leading into said fuel conduit to supply additional fuel forcold running, means for delivering pressurized'fuel to said enrichmentpassageway at a pressure higher than the pressure in said fuel conduitdownstream of said orifice, and a temperature responsive valve means insaid enrichment passageway and operative to close with increase inengine temperature.

21. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel tothe conduit in proportion to the speedof'an engine, a control conduit branching from the fuel conduit, a fuelflow control connected to deliver fuelto the engine in accordance withpressures in said conduits, and means for automatically decreasing thesize of the fuel flow, conduit I'CSPOD: sive to a signal wherebypressure is momentarily increased to cause said fuel flow control tosupply a rapid fuel increase to the engine.

22. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speed,of. an engine, a control conduit branching from the fuel conduit, a fuelflow control connected to deliver fuel to the engine in accordance withpressures in said conduits, and pressure responsive means connected tothe intake manifold of .the engine and connected to said fuel conduitand operative to automatically and instantaneously cause a change inpressure in said fuel conduit without directly. affecting the pressurein said control conduit causing an immediate increase in the fuelsupplied to the engine by said fuel flow control with an increase inintake manifold pressure.

23. A fuel'supply me hanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speedof an engine,, a control conduit branching from the fuel conduit, a fuelflow control connected to deliver fuel to the engine in accordance withpressures in said conduits, a fuel reservoir connected to supply fueldirectly to said fuel conduit, and pressure responsive means connectedto the intake manifold of the engine and connected to cause a how offuel from said reservoir to said conduit with acceleration of the engineto improve the dynamic response.

24. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speedof an engine, acontrol conduit branching from the fuel conduit, afuclflow control connected to deliver fuel to the engine in accordancewith pressures in said conduits, a chamber opening into said fuelconduit, a pressure balanced movable piston in said chamber exposed tothe fuel on one side and movable toward the fuel conduit to dischargefuel from the chamber into the fuel conduit, a biasing means urging thepiston toward the conduit, and means connecting the chamber to exposethe other side of the piston to the pressure of the intake manifold ofthe engine whereby sudden decreases in pressure will cause a rapiddynamic response in increased fuel supply to the engine.

25. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the flow of fuel to anengine, pump means for supplying fuel to said conduit in proportion tothe speed of the engine, means for pressurizing the inlet side of saidpump means, a pressure drop orifice in said conduit, fuel flow controlmeans for supplying fuel to the engine in accordance with pressure insaid fuel flow conduit, a displacement compensating passageway extendingaround said pump means and connected to the pump inlet and to said fuelconduit downstream of said orifice to vary the pressure in said conduit,a displacement compensation valve in said passageway, and means foradjusting said valve to a fixed opening whereby the quantity of fuelflowing in said fuel conduit is afiected linearly proportional to speedand as a function of the adjustment setting of said valve to use thesystem for engines of different displacement.

26. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the flow of fuel to anengine, pump means for supplying fuel to said conduit in proportion tothe speed of the engine, a control conduit branching from the fuelconduit, a fuel flow control connected to deliver fuel to the engine inaccordance with pressures in said conduits, a displacement compensationpassageway connected to said fuel conduit, a displacement compensationvalve in said-passageway, and means for adjusting said valve to a fixedopening whereby the quantity of fuel flowing in said fuel conduit isaffected linearly proportional to speed and as a function of theadjustment setting of said valve to use the system for engines ofdifferent displacement.

27. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the fiow of fuel to anengine, a first pump in said fuel flow conduit delivering fuelproportional to engine speed, a second pump in said fuel flow conduitreceiving fuel from the first pump and having a positive displacement,said second pump being driven by the engine and having a speed which isa linear function of engine speed, a pressure responsive valvecommunicating with the discharge side and intake side of said secondpump and responsive to pressure differential and removing fuel from theintake side and holding the pressures equal whereby the output of thesecond pump is accurately proportional to engine speed, a fixed orificedownstream from said second pump, and a variable orifice downstream fromsaid second pump, said orifices being of a size with respect to pumpdischarge to have a very small'pressure drop at low engine speed toreduce the pressure difierential between the discharge and intake ofsaid second pump at low engine speeds to reduce the amount of fuel whichby-passes said second pump through said pressure responsive valve.

28. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the flow of fuel to anengine, means supplying fuel to the conduit in proportion to the speedof an engine, a control conduit branching from the fuel conduit, avariable orifice between the fuel conduit and the control conduit, meansclosing said variable orifice when said engine is stopped, a flowcontrol supplying fuel to the engine as a function of pressures in saidconduits and stopping the flow when the pressure in the control conduitis equal to that in the fuel conduit, passageways from the controlconduit, means automatically opening said passageways when the engine isstopped, and means for equalizing the pressure in the fuel conduit tothat in the control conduit when the engine is stopped to cause saidfuel fiow control to prevent the flow of fuel to the engine.

29. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the flow of fuel to anengine, means supplying fuel to the conduit in proportion to the speedof an engine, a control conduit branching from the fuel conduit, anorifice between the fuel conduit and the control conduit, means openingsaid orifice when said engine is stopped, flow control means responsiveto pressures in said conduits and operative to prevent the flow of fuelwhen the pressure in the fuel conduit drops to a predetermined levelrelative to pressures in the control conduit, and means automaticallyventing the system when the engine is stopped to cause said flow controlmeans to prevent the flow of fuel to the engine.

30. A fuel supply control system for an engine com.- prising incombination a fuel fiow conduit for supplying and controlling the flowof fuel to an engine, means supplying fuel to the conduit in proportionto the speed of an engine, a control conduit branching from the fuelconduit, a variable orifice between the fuel conduit and controlconduit, means closing said variable orifice when said engine isstopped, flow control means operative to deliver fuel to the engine as afunction of pressures in said conduits and to stop flow when thepressure equalizes in the fuel conduit and the control conduit, a bleedorifice from the control conduit, 3. pressure relief passageway leadingfrom said fuel conduit to said control conduit, a bleed shutoff valve insaid control passageway in series with the bleed orifice, and meansresponsive to control conduit pressure operative to close said pressurerelief passageway and open said bleed shutoif valve during engineoperation and to close the bleed shutofi valve and open the pressurerelief passageway when the engine is stopped to stop flow of fuel to theengine by operation of the flow control means.

31. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the flow of fuel to anengine, positive displacement pump means for supplying fuel to saidconduit in proportion to the speed of the, engine and driven at a speedproportional to engine speed, a control conduit branching from the fuelconduit, a fuel flow control connected to deliver fuel to the engine inaccordance with pressures in said conduits, and means for changing thepressure in said control conduit during engine cranking for increasingfuel delivered by said fuel flow control.

32. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the fioW of fuel to anengine, a control conduit, valve means between the conduit and controlconduit whereby a lower pressure is established in said control conduit,means delivering fuel to the engine proportional to pressures in saidfuel conduit and said control conduit positive displacement pump meansfor supplying fuel to said conduit in proportion to the speed of theengine and driven at a speed proportional to engine speed, a boosterpump delivering fuel to the inlet of said pump means to supply pressurefor starting the engine when said pump means operates at low crankingspeeds, at variable idle mixture orifice in said control conduit, anescape orifice leading from said control conduit downstream of said idlemixture orifice and communicating with the intake to said pump means, arelief starting enrichment valve having a valve port between said escapeorifice and said idle mixture orifice, and means to open the enrichmentvalve permitting the escape of fuel from the booster pump to flowthrough said enrichment valve during starting and 19 lowering pressurein said control conduit to increase fuel delivery to the engine.

33. A fuel supply control system for an engine comprising in combinationa fuel flow conduit for supplying and controlling the flow of fuel to anengine, positive disin proportion to the speed of the engine and drivenat a speed proportional to engine speed, a booster pump delivering fuelto the inlet of said pump means to supply pressure for starting theengine when said pump means operates at low cranking speeds, a controlconduit branching from the fuel conduit, a fuel flow control connectedto deliver fuel to the engine in accordance with pressure in said fuelconduits and pressure at one end of said control conduit, a variableidle mixture orifice in said control conduit, an escape orifice leadingfrom said control orifice downstream of said idle mixture orifice andcommunicating with the intake to said pump means, a relief startingenrichment valve having a valve port between said escape orifice andsaid idle mixture orifice, means to operate the valve permitting theescape of fuel from the booster pump flowing through said escape orificeduring starting, said relief valve also operative to close the controlconduit between said idle mixture orifice and said relief valve portwhereby said fuel flow control is exposed to control conduit pressurebetween said escape orifice and said enrichment valve, and a smallby-pass port around said relief valve feeding fluid pressure from theidle mixture orifice to said one end of the control conduit.

34. A control system in accordance with claim 33 wherein a heatresponsive valve member is located in the opening of at least one ofsaid ports to determine its opening in accordance with enginetemperatures.

35. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speedof an engine, a control conduit branching from the fuel conduit, a fuelflow control connected to deliver fuel to the engine in accordance withpressures in said conduits, a closed housing having a limp diaphragmthereacross clamped at its edge dividing the housing into a firstchamber and a second chamber with the first chamber exposed to thepressure of said control conduit and the second chamber exposed to thepressure of the fuel conduit, a valve seat in said second chamber lyingin a plane defined by the clamped edges of said diaphragm, and a valveclosing member supported by the diaphragm in the plane of said diaphragmedge to engage the valve seat when the diaphragm is in unstressedcondition.

36. In a fuel supply system for an engine including a fuel flow conduit,means supplying fuel to the conduit inproportion to the speed of anengine, a control conduit branching from the fuel conduit, a fuel flowcontrol connected to deliver fuel to the enginein accordance withplacement pump means for supplying fuel to said conduit pressures insaid conduits comprising a closed housing having a limp diaphragmthereacross clamped at its edge dividing the housing into a firstchamber and a second chamber with the first chamber exposed to thepressure of said control conduit and the second chamber exposed to thepressure of the fuel conduit, a valve seat in said second chamber lyingin a plane defined by the clamped edge of said diaphragm, a valveclosing member sup ported by the diaphragm in the plane of saiddiaphragm edge to engage the valve seat when the diaphragm is inunstressed condition, and means supporting a valve closing member andhaving an annular opening to fit over said seat with a closing memberrecessed in said supporting means and carried in the plane of saiddiaphragm clamping means when engaging said seat.

37. A fuel supply mechanism for an engine comprising a fuel flowconduit, means supplying fuel to the conduit in proportion to the speedof an engine, a control conduit branching from the fuel conduit, a fuelflow control connected to deliver fuel to the engine in accordance withpressures in said conduits comprising a closed housing having a limpdiaphragm thereacross clamped at its edge dividing the housing into afirst chamber and a second chamber with the first chamber exposed to thepressure of said control conduit and the second chamber exposed to thepressure of the fuel conduit, a valve seat carried by said diaphragm, anintake manifold for the engine, a passageway leading from said valveseat to said manifold, and a spacer member having a flow paththerethrough forming part of said passageway and formed of insulatingmaterial and consisting of the only heat flow path between said manifoldand diaphragm housing.

38. The method of regulating a supply of fuel to an internal combustionengine which comprises the steps of establishing a path for flow of fuelfrom a fuel source to the intake of an engine, restricting the area ofthe flow path at a given point therealong to a predetermined area,delivering the fuel along the flow path at a rate pro portional to thespeed of operation of the engine, providing a flow path around saidrestricted area and permitting flow therethrough as a function of theengine speed and as a function of the volumetric efiiciency of theengine to supply fuel to the flow path downstream of the restrictedarea, and delivering fuel up to the engine in accordance with flowconditions in said flow path down stream of said restricted area.

References Cited in the file of this patent UNITED STATES PATENTS2,696,405 Noon Dec. 7, 1954 2,785,669 Armstrong Mar. 19, 1957 2,803,233Demtchenko Aug. 20, 1957

